Thanks for your reply, Triton.
Greg & I have not been on Princess's smaller ships. My only concern is that your first "Princess experience" will be on a smaller ship that was not ordered or designed by Princess. As I'm sure you already know, Tahitian Princess was formerly "R Four" of Renaissance Cruises. From what I've seen and those I've spoken to, TP doesn't have the same type of ambiance that the line traditionally aims for like large/spacious lobbies, light woods, intimate areas, overall design, etc. The dark woods and ship configuration, especially, may lead some to believe that those were chosen by Princess. While I have zero doubt that the staff will be excellent and your cruise wonderful, it's human nature to naturally compare surroundings with what we already know. In this instance, I'm afraid Celebrity may win in comparison.
Because Greg & I have sailed on a couple of different Princess ships before, I'm tempted to try a smaller ship for comparison's sake. Please be sure to keep all of us informed on your thoughts after the cruise - I would LOVE to hear what you think.
Wishing you a great time on your upcoming journey,